[sane-devel] making scanbd work OOTB in debian - question about supported backends

[Wilhelm]

Am 04.03.2015 um 06:26 schrieb Rolf Leggewie:
> On 28.02.2015 16:27, Wilhelm wrote:
>> Am 25.02.2015 um 07:06 schrieb Rolf Leggewie:
>>> Hello,
>>>
>>> I am maintaining scanbd in Debian and found scanbd difficult to
>>> configure with lots of possible pitfalls.  As much as possible I want to
>>> make it easy and failproof for the ordinary users to install and use
>>> scanbd OOTB.
>>>
>>> One of the things that broke things for me and that were hard to
>>> troubleshoot (I wrote to this ML about it last year) is that the SANE
>>> backend configurations need to be present both in /etc/sane.d and
>>> /etc/scanbd.  This is due to the nature scanbd sits on top of SANE. I
>>> still wonder if scanbd couldn't be made to have an explicit
>>> SANE_BACKEND_CONFIG_DIR in addition to the SANE_CONFIG_DIR?!  That would
>>> eliminate the need for what I am about to explain.
>>
>> What should be the effect of this env-variable SANE_BACKEND_CONFIG_DIR?
>>
>> I think it would be best, if the SANE lib would support setting
>> explicitly the config file (dll.conf) and / or the config dir.
>>
>> Then saned could use this and introduced a -c <config-file> and / or
>> -d<dir> options. And in turn scanbd can make use of this.
> 
> I thought I had already replied to this message but I cannot see it in
> the archive.  My apologies if this comes out as a double-post.
> 
> As maintainer, I currently need to copy all backend files from
> /etc/sane.d/*.conf to /etc/scanbd.  That is messy to say the least.  If
> SANE_BACKEND_CONFIG_DIR was a variable separate from SANE_CONFIG_DIR
> that wouldn't be necessary with obvious benefits to everyone.

All SANE desktop applications use SANE_CONFIG_DIR. scanbd must use saned
with a different dll.conf and therefore sets SANE_CONFIG_DIR before
invoking saned. SANElib looks for that dll.conf and config-files in
there and dll.d. The point is, that you can't direct SANE to another
dll.conf. And I don't see what the help of SANE_BACKEND_CONFIG_DIR could
be in this respect.

But: is SANE_BACKEND_CONFIG_DIR a SANElib env-variable? Don't know about it.


> 
> I do believe that your suggestion of saned having a -d or -c parameter
> would likely achieve the same result, alas, we don't have it and it's
> not clear it will arrive.
> 


-- 
Wilhelm
w.meier at unix.net